Dry cleaning machine

ABSTRACT

A dry cleaning machine is disclosed, including a storage tank for storing a supply of liquid cleaning solvent, a cleaning chamber for receiving articles to be cleaned and a fluid communication means, including a filter, for transferring liquid solvent from the storage tank to the chamber. The machine also includes means for periodically removing impurities from the filter comprising a trap connected to the filter via a normally closed first valve and having a removable cover. A foraminous bucket is disposed within the trap and is removable therefrom when the cover is removed from the trap. A source of compressed gas is connectable to the trap via a normally closed second valve. Also, means are connected between the fluid communication means and the filter for backwashing the filter with liquid solvent from the storage tank. After each wash cycle, the first valve is opened and the filter backwashed to flush impurities in the filter into the trap where the impurities are retained in the bucket. Thereafter the first valve is closed, and the second valve is opened to admit compressed gas into the trap to squeeze liquid solvent from the impurities retained in the bucket. The second valve is then closed. Periodically the cover is removed from the trap so that the bucket may be removed therefrom and the impurities retained in the bucket discarded. The machine also includes means for removing solvent vapor from the cleaning chamber during each drying cycle and condensing such vapor. The vapor removal and condensing means includes a vacuum pump connected to the chamber for removing solvent vapor therefrom, a condensation vessel connected to the vacuum pump for condensing solvent vapor removed from the chamber, a transfer pump connected to the condensation vessel for removing solvent vapor therefrom, a pressure vessel connected to the transfer pump for condensing solvent vapor removed from the condensation vessel and an additional storage tank for storing liquid solvent condensed in the condensation and pressure vessels. The transfer pump reduces the pressure of the gases in the condensation vessel and thereby reduces the pressure head against which the vacuum pump operates.

waited States Patent 1 Quackenbush [11] 3,773,33 l lNov. 13, 1973 DRYCLEANING MACHINE Henry Quackenbush, 1461 S. Broad St., Mobile, Ala.36605 [76] lnventor:

[52] [1.3. CI 68/18 C, 68/18 F [51] Int. Cl. D06f 43/08 [58] Field OfSearch 68/18 C, 18 G, 18 F, 618/18 R [56] References Cited UNITED STATESPATENTS 3,270,531 9/1966 Czech 68/18 F 3,323,335 6/1967 Schneider 68/18R 3,388,567 6/1968 Oles 68/18 R 3,674,650 7/1972 Fines 68/18 C 3,692,4679/1972 Durr et al. 68/18 C FOREIGN PATENTS OR APPLICATIONS 1,076,0662/1960 Germany 68/18 C Primary Examiner-John Petrakes AssistantExaminerGary R. Robinson Attorney-Birch, Swindler, McKie & Beckett [57]ABSTRACT A dry cleaning machine is disclosed, including a stor- AMBIENTATMOSPHERE COMPRESSED age tank for storing a supply of liquid cleaningsolvent,

a cleaning chamber for receiving articles to be cleaned for transferringliquid solvent from the storage tank to the chamber. The machine alsoincludes means for periodically removing impurities from the filtercomprising a trap connected to the filter via a normally closed firstvalve and having a removable cover. A foraminous bucket is disposedwithin the trap and is removable therefrom when the cover is removedfrom the trap. A source of compressed gas is connectable to the trap viaa normally closed second valve. Also, means are connected between thefluid communication means and the filter for backwashing the filter withliquid solvent from the storage tank. After each wash cycle, the firstvalve is opened and the filter backwashed to flush'impurities inthefilter into the trap where the impurities are retained in the bucket.Thereafter the first valve is closed, and the second valve is opened toadmit compressed gas into the trap to squeeze liquid solvent from theimpurities retained in the bucket. The second valve is then closed.Periodically the cover is removed from the trap so that the bucket maybe removed therefrom and the impurities retained in the bucketdiscarded.

15 Claims, 4 Drawing Figures AIR PATENTED NOV 13 I973 SHEET 10F 2 lllllI NM m 8 Mlir- My;

EmwmEzoQ PATENTED HOV 131975 SHEET 2 BF 2 WATER 8 V 000 9 oo 00 oo 00000 00000000 kooooooo 9 0000000 ooooooo 0000000 000 000 000 000 00 o O 40 9 9 FIGS DRY CLEANING MACHINE BACKGROUND OF THE INVENTION 1. Field ofthe Invention This invention relates to dry cleaning machines, andspecifically to a dry cleaning machine having a closed fluid handlingsystem for retaining and recycling clean ing solvent.

2. Description of the Prior Art Many dry cleaning machines are knownhaving closed fluid handling systems for retaining and recyclingcleaning solvent. Exemplary of such machines are those disclosed inBehrens U.S. Pat. No. 3,106,831, Stanulis et al U.S. Pat. No. 3,122,908,Gosnell U.S. Pat. No. 3,254,513, Shaw U.S. Pat. No. 3,269,155, CzechPat. No. 3,270,531, Schneider U.S. Pat. No. 3,323,335, Oles U.S. Pat.No. 3,388,567, Dickey U.S. Pat. No. 3,410,118 and McCutcheon U.S. Pat.No. 3,426,555. The closed fluid handling systems of some of thesemachines, for example, the machine disclosed in the Schneider patent,include one or more vacuum pumps for removing solvent vapor from thecleaning chamber. However, in these machines the vacuum pumps arearranged such that the pumps must operate against a substantial pressurehead, thereby requiring the use of relatively large capacity vacuumpumps which are relatively expensive to operate and maintain.

Also, while most of the prior art-dry cleaning machines include a filterfor removing impurities from the liquid cleaning solvent prior to thesolvent entering the cleaning chamber, such machines do not include anymeans for quicklyand easily removing the impurities from the filter. I

SUMMARY OF THE INVENTION The dry cleaning machine of the presentinvention embodies optimum solutions to the foregoing disadvantages ofthe prior art machines.

Basically described, the machine comprises; a tank for storing a supplyof liquid cleaning solvent; a cleaning chamber for receiving articles tobe cleaned; a first fluid communication means connected between thestorage tank and the chamber for transferring liquid solvent from thetank to the chamber and including a filter for removing impurities fromthe solvent; a sec- 0nd fluid communication means connected between thechamber and the storage tank for returning liquid solvent from thechamber to the tank; means for removing solvent vapor from the chamberand condensing suchvapor; and means for removing impurities from thefilter comprising, a trap in fluid communication with the storage tankand including a removable cover, a foraminous bucket for retainingimpurities therein disposed in the trap and removable therefrom when thecover is removed from the trap, a normally closed first valve meansconnected between the filter and the trap for selectively placing thefilter in fluid communication with the trap, a normally closed secondvalve means connected to the trap and connectable to a source ofcompressed gas for selectively admitting compressed gas into the trap,and means connected between the first fluid communication means and thefilter for backwashing the filter with liquid solvent from the storagetank, whereby the first valve means is opened and the filter backwashedso that impurities in the filter are flushed into the trap and retainedin the bucket, whereafter the first valve means is closed and the secondvalve means is opened so that compressed gas is admitted into the trapto squeeze solvent from the retained impurities, whereafter the secondvalve means is closed, whereupon the cover may be removed from the trapand the bucket removed therefrom so that the impurities retained in thebucket may be discarded.

The solvent vapor removal and condensing means preferably comprises avacuum pump connected to the chamber for removing solvent vaportherefrom, a condensation vessel connected to the vacuum pump forcondensing solvent vapor removed from the chamber, a transfer pumpconnected to the condensation vessel for removing solvent vaportherefrom, a pressure vessel connected to the transfer pump forcondensing solvent vapor removed from the condensation vessel, and anadditional storage tank connected to the condensation and pressurevessels for storing liquid solvent condensed in such vessels.

A basket is rotatably mounted in the cleaning chamber for holding thearticles to be cleaned and preferably has a plurality of perforationstherein to facilitate the flow of gases through the basket and thearticles therein. Also, a fan preferably is rotatably mounted in thechamber concentric with respect to the basket to promote the circulationof gases through the basket and the articles therein.

A heatexchanger also preferably is mounted in the chamber to selectivelyheat and cool the gases within the chamber to facilitate the removal ofsolvent vapor therefrom during each drying cycle.

If desired, the machine may include a still for distilling contaminatedsolvent and transferring distilled solvent to the additional storagetank.

With the foregoing in mind, it is an object of the present invention toprovide an improved dry cleaning machine.

It is a further object of the invention to provide a dry cleaningmachinehaving an improved closed fluid handling system for retaining andrecycling cleaning solvent.

It is an additional object of the invention to provide a dry cleaningmachine as described in the preceding object in which the fluid handlingsystem includes a vacuum pump connected to a cleaning chamber and acondensation means connected to the vacuum pump for condensing solventvapor removed from the chamber by the vacuum pump, which latter meansincludes means for reducing thepressure head against which the vacuumpump operates.

It is also an object of the invention to provide a dry cleaning machinehaving a filter interposed between a primary solvent storage tank and acleaning chamber and means for periodically removing impurities from thefilter quickly and easily.

It is an additional object of the invention to provide a dry cleaningmachine having a basket mounted in" a cleaning chamber for holdingarticles to be cleaned and means to facilitate and promote thecirculation of gases through the basket and through the articlestherein.

These and other objects of the invention will become apparent upon aconsideration of the following detailed description of a preferredembodiment thereof giving in connection with the following drawings,wherein like reference numerals identify like elements throughout.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERREDEMBODIMENT The dry cleaning machine of the invention is shownschematically in FIG. 1, as designated by reference numeral 10. Machineincludes a primary storage tank 12 for storing a supply of liquidcleaning solvent, such as a chloronated or flourocarbon cleaningsolvent. The machine also includes a cleaning chamber 14 for 'receivingarticles to be cleaned and a fluid communication means 16 fortransferring liquid cleaning solvent from tank 12 to chamber 14.Communication means 16 comprises a pump 18 having the inlet thereofconnected to tank 12 by a conduit 20. The outlet of pump 18 is connectedto the inlet of a filter 24 by a conduit 22 having a valve 26 interposedtherein. The outlet of filter 24 is connected to chamber 14 by a conduit28 having a valve 30 interposed therein. The normal or forward flowthrough the filter is from the inlet to which conduit 22 is connected tothe outlet to which conduit 28 is connected. Filter 24 removesimpurities from the solvent prior to the solvent entering chamber 14. Aswill be apparent, cleaning solvent is transferred from tank 12 tochamber 14 via conduit 20, pump 18, conduit 22, filter 24 and conduit28.

Machine 10 further includes means for removing impurities from filter24. Such means comprises a trap 32 in fluid communication with storagetank 12 via a conduit 34. Trap 32 is connected to the backwash outlet offilter 24 by a conduit 36 having a normally closed valve 38 interposedtherein. Another conduit 40 also is connected to trap 32 having anormally closed valve 42 interposed therein. Conduit 40 is adapted to beconnected to a source of compressed gas, such as a conventional aircompressor (not shown).

Trap 32 and the components associated therewith are shown in detail inFIG. 2, and include a cover 44 which is removably secured to the trap bya clamp assembly 46. Assembly 46 includes a substantially C- shapedclamp 48 having a pair of opposed flanges 50 which are engageable withan annular flange 52 affixed about the upper end of trap 32. A clampingbolt 54 is threadably received through clamp 46 and is engageable withthe upper surface of cover 44 to urge the cover downwardly againstflange 52 to thereby secure the cover to the tank. A toggle-type handle56 is affixed to the outer end of bolt 54 to facilitate turning thebolt. A sealing ring 58 is retained in flange 52 and is engageable withthe periphery of cover 44 to seal the cover on trap 32. To remove thecover from the trap, bolt 54 is backed away from engagement with thecover by turning handle 56 to thereby loosen clamp 48. The clamp is thenremoved from the trap by sliding it horizontally so that flanges 50disengage flange 52. The cover may then be removedfrom the trap bymerely grasping the peripheral edge of the cover and lifting itupwardly.

A bucket 60 is disposed in trap 32 and has a foraminous bottom 62 whichis covered by a fine wire mesh screen 64. An annular flange 66 isaffixed to the upper end of bucket 60 and engages a sealing ring 68 supported on an annular flange 70 affixed to the inner wall of trap 32. Apair of handles 72 are afiixed to the inner wall of bucket 60 tofacilitate removal and insertion of the bucket into trap 32.

A branch conduit 74 is connected between conduit 22 and the backwashinlet of filter 24. Conduit 74 is connected to conduit 22 between theoutlet of pump 18 and valve 26 and has a normally closed valve 76interposed therein. The backwash or reverse flow through filter 24 isfrom the backwash inlet to which conduit 74 is connected to the backwashoutlet to which conduit 36 is connected.

A branch conduit 78 is connected between conduit 28 and tank 12. Conduit78 is connected to conduit 28 between the outlet of filter 24 and valve30 and has a normally closed valve 80 interposed therein.

To remove impurities from filter 24, valves 26, 30 and 80 are closed andvalves 76 and 38 opened. Liquid solvent is then pumped through filter24in the backwash direction to flush the impurities in the filter intotrap 32 through conduit 36. The impurities are retained in bucket 60 andthe solvent returns to tank 12 through conduit 34. Thereafter, valves 76and 38 are closed and valve 42 opened to admit compressed gas into trap32 to squeeze liquid solvent from the impurities retained in bucket 60.The impurities generally consist of lint, threads and the like and areknown in the art as muck. Thereafter, valve 42 is closed. Cover 44 maythen be removed from trap 32 as described above and bucket 60 removedfrom the trap so that the impurities retained in the bucket may bediscarded. Generally, impurities are removed from filter 24 in theforegoing manner after every wash cycle and from bucket 60 at least oncedaily under normal operating conditions.

Immediately following the removal of impurities from filter 24, valves26 and 80 are opened and valve 30 maintained closed. The filter elementsof the filter may then be coated with conventional filtering agents,such as diatomaceous earth and activated charcoal, by introducing suchagents into the flow of solvent through the filter in the normaldirection. Generally, the filtering agents are introduced into the flowat pump 18. The solvent is returned directly from filter 24 to storagetank 12 through conduit 78 until the filter elements are coated. Valve80 is then closed and valve 30 opened. Fluid communication ineans 16 isthen prepared to again transfer liquid solvent from tank 12 to chamber14 from the subsequent wash cycle.

Chamber 14 is connected to storage tank 12 by a fluid communicationmeans comprising a conduit 82 having a valve 84 interposed therein. Uponthe completion of each wash cycle, liquid solvent is returned fromchamber 14 to tank 12 via conduit 82 by opening valve 84. Also, chamber14 is connected to tank 12 by a conduit l 18 for controlling the levelof liquid solvent in the chamber. As shown in FIG. 1, conduit 1 18 isconnected to the side of the chamber at a point which is approximatelyone-third the height of the chamber from the bottom thereof, and has avalve interposed therein. Chamber l4 and the associated components areshown in detail in FIG. 3, and include a base 86 on which the chamber ismounted. A generally cylindrically shaped basket 88 is rotatably mountedwithin the chamber for holding articles to be cleaned and has an opening90 in the front wall thereof through which the articles are placed intoand removed from the basket. Opening 90 communicates with an opening 94in the front wall of chamber 14, and a hermetically scalable door 96 isremovably secured over opening 94 to hermetically seal the chamber for areason described in detail below. Basket 88 has a plurality ofperforations 98 in the side and rear walls thereof to facilitate thecirculation of gases through the basket and the articles therein. Also,a fan 100 may be rotatably mounted in chamber 14 concentric with respectto basket 88.

Basket 88 and fan 100 are secured to a shaft 102 which extends through asupporting bearing 104 affixed to the rear wall of chamber 14. Anelectric motor 106 is mounted on base 86 and is drivingly connected tothe outer end of shaft 102 by a belt and pulley system 108. As will beapparent, basket 88 and fan 100 are selectively rotatably driven bymotor 106 via system 108 and shaft 102.

A heat exchanger 110, and preferably of the type operated by steam, alsois mounted in chamber 14 and is adapted to be connected to aconventional source of steam, such as a boiler (not shown), by a conduit112 having a valve 113 interposed therein. Heat exchanger 110 also isadapted to be connected to a source of ambient temperature water by abranch conduit 114 connected to conduit 112 between the heat exchangerand valve 113 and having a valve 115 interposed therein. Also, a conduit1 16 is connected to the heat exchanger for draining steam and/or watertherefrom. The operation of heat exchanger 1 in relation to the othercomponents of machine 10 is described below.

A temperature sensitive control element, such as a thermostat 182, ismounted in chamber 14 (FIG. 3) and is operatively connected to valve 113for controlling the admission of steam into heat exchanger 110. Also, asolvent vapor sensing element 184 is mounted in chamber 14 and isoperatively connected to valves 113 and 115 for terminating theadmission of steam into heat exchanger 110 and initiating the admissionof cooling water therein as described below. A conduit 122 is connectedto chamber 14, communicating with the lower portion thereof for a reasondescribed below, and has a valve 124 interposed therein. In addition, aconduit 126 is connected between chamber 14 and ambient atmosphere andhas a valve 128 interposed therein.

The sequence of operations comprising the wash cycle of machine 10 areas follows. The articles to be cleanedare placed in basket 88 and door96 closed. Valves 26, 30 and 120 are then opened, and valves 38, 42, 76,80, 84, 124 and 128 closed. Liquid cleaning solvent is then transferredfrom tank 12 to chamber 14 by fluid communication means 16 in the mannerdescribed above. Any liquid solvent transferred to chamber 14 in excessof the amount required to fill the chamber to the height at whichconduit 118 is connected thereto is returned to tank 12 via conduit 118.At this time, heat exchanger 110 is at ambient temperature. Motor 106 isthen energized to rotate basket 88 with the articles to be cleanedtherein so that the articles are washed in the liquid solvent withinchamber 14. At the conclusion of the wash cycle, valve 84 is opened andliquid solvent returns from chamber 14 to tank 12 through conduit 82.Also, impurities are removed from filter 24 in the manner describedabove.

An extract cycle follows the wash cycle during which basket 88 isrotated at a relatively high rotary velocity to squeeze liquid solventfrom the articles in basket 88 by centrifugal force. At this time, valve113 is opened to admit stream into heat exchanger to heat the gaseswithin chamber 14. The liquid solvent squeezed from the articles inbasket 88 is returned to tank 12 through conduit 82. I

A drying cycle follows the wash and extract cycles during whichsubstantially all solvent vapor in chamber 14, including any solventremaining on the articles in basket 88 following the extract cycle, isremoved from the chamber and condensed by a solvent vapor removal andcondensing means 130. Means 130 includes conduit 122 which is connectedby a branch conduit 132 to the inlet of a vacuum pump 134. The outlet ofvacuum pump 134 is connected to a vapor condensation means 135. Thefirst stage of condensation means 135 comprises a condenser 138 which isconnected to the outlet of pump 134 by a conduit 136. Condenser 138 isconnected by a conduit 140 to a condensation vessel 142 comprising thesecond stage of condensation means 135. Solvent vapor removed fromchamber 14 by pump 134 is cooled in condenser 138 and partiallycondensed in vessel 142.

Pump 134 is of the liquid seal type to prevent the solvent vapor removedfrom chamber 14 from becoming contaminated with conventional lubricants.Liquid solvent for sealing pump 134 is obtained from vessel 142 and istransferred to the pump through a conduit 144 connected between thelower portion of vessel 142 and the sealing chamber of the pump.

The upper portion of vessel 142 is connected by a conduit 148 to theinlet of a compressor type transfer pump 146 comprising the third stageof condensation means 135. The outlet of pump 146 is connected by aconduit 150 to a condenser 152 comprising the fourth stage of thecondensation means. Finally, condenser 152 is connected by a conduit 154to a pressure vessel 156 comprising the fifth and final stage of thecondensation means. Solvent vapor is removed from the upper portion ofvessel 142 by pump 146 and cooled in condenser 152 prior to the vaporentering pressure vessel 156. Cooling water for condensers 138 and 152is supplied through a bifurcated conduit 158 having a branch connectedto the inlet of each condenser and a valve 160 interposed therein.

A float valve 162 is mounted in vessel 156 for controlling the level ofliquid solvent condensed in the vessel. Float valve 162 is connected bya conduit 164 to a means for separating water from liquid solvent.

A branch conduit 166 having a check valve 168 interposed therein isconnected between vessel 142 and conduit 164. Valve 168 permits liquidsolvent to flow out of vessel 142 into conduit 164, but prevents thereverse flow of solvent. Conduit 166 is connected to the side of vessel142 at the height desired for the level of liquid solvent in the vessl.

A conduit 170 is connected between the upper portion of vessel 156 andambient atmosphere and has a pressure release valve 172 interposedtherein. When the pressure in vessel 166 reaches a predetermined amount,such as 80 psi, valve 172 releases compressed gases to the atmospherethrough conduit 170. Since solvent vapor is more dense than air, thevapor will settle to the mid-portion of vessel 156 and compressed airwill accumulate in the upper portion of the vessel. Therefore, the gasesreleased to atmosphere through conduit 170 comprise compressed air.Thus, the solvent vapor does not escape from the fluid handling systemof machine 10 and pollute the atmosphere but is condensed as liquidsolvent.

The means for separating water from liquid solvent comprises a tank 174having an internal baffle 176 which divides the tank into two chambers173 and 175. Since liquid solvent is more dense than water, the solventwill settle to the bottom of tank 174 and flow under baffle 176 intochamber 175, while any water in the solvent will accumulate on thesurface of the solvent in chamber 173. The water may thus be drainedfrom the upper portion of chamber 173 while waterfree solvent may beremoved from chamber 175. A conduit 178 connects chamber 175 to astorage tank 180 in which water-free condensed liquid solvent is stored.

The sequence of operations comprising the drying cycle of machine 10 areas follows. Upon the completion of the extract cycle which isdeterminedby the temperature in chamber 14 as described below, valves 30, 84, 120and 128 are closed and valve 124 opened. Vacuum pump 134 and transferpump 146 are then energized to remove solvent vapor from chamber 14which is cooled in condensers 138 and 152 and condensed in vessels 142and 156 as described above. Since the volume of vessel 142 above thelevel of liquid solvent therein is less than the volum of chamber 14, ifthe vapor was condensed in vessel 142 alone, vacuum pump 134 would berequired to establish and maintain a significant pressure head withinthe vessel.

This would require the use of a relatively large capacity vacuum pumpwhich is relatively expensive to operate and maintain. By employingtransfer pump 146 and pressure vessel 156, the necessity of employing alarge capacity vacuum pump is eliminated. Transfer pump 146 removessolvent vapor from the upper portion of vessel 142 and thus reduces thepressure head against which vacuum pump 134 operates.

Thermostat 182 terminates the extract cycle and initiates the dryingcycle when the gases within chamber 14 have reached a predeterminedtemperature. The predetermined temperature is at least as high as thevaporization temperature of the solvent at the reduced pressureestablished in chamber 14 by vacuum pump 134. This temperature ismaintained until substantially all solvent vapor has been removed fromthe chamber. For example, if perchlorethylene is employed as thesolvent, the solvent will vaporize at a temperature of approximately 140F at a pressure slightly less than 27 inches of mercury. Since thesolvent vapor is more dense than air, the vapor will tend to settle inthe lower portion of chamber 14, thus, as described above, conduit 122communicates with the lower portion of the chamber.

During the drying cycle, basket 88 and fan 100 are rotatably driven at arelatively high rotary velocity so that the gases within chamber 14 arecirculated through basket 88 and the articles therein to facilitate thevaporization of the solvent on the articles. The gases flow out of thebasket through perforations 98 in the sidewall thereof, then rearwardlyin the annular passage defined between the sidewalls of the basket andchamber 14 and back into the basket through the perforations 98 in therear wall thereof.

Element 184 senses when substantially all of the vapor has been removedfrom chamber 14 and then closes valve 113, and opens valve 115. Coolingwater is then admitted to heat exchange to cool the gases within chamber14 and the articles in basket 88 to ambient temperature. During thecooling of chamber 14, valve 128 is opened to admit ambient air into thechamber. Pumps 134 and 146 continue to operate for a short period oftime after valve 128 is opened to prevent the abrupt condensation ofatmospheric water vapor in the chamber which would wet the articles inbasket 88.

Pumps 134 and 146 are thereafter de-energized and valve 124 is closed.The interior of chamber 14 is now at ambient temperature and pressurewith the articles in basket 88 in a clean dry condition.

If desired, machine 10 also may include a still 186 having the inputthereof cnnected to a contaminated solvent storage tank 194 by a conduit188. The solvent in tank 12 becomes contaminatedafter prolonged use andis transferred to tank 194 by any conventional fluid communicationmeans.

In still 186, contaminated solvent is distilled, and distilled liquidsolvent removed fromthe still through conduit 190. When it is desired tooperate still 186, valve 124 is closed and valve 192 opened. Vacuum pump134 and transfer pump 146 are then energized to reduce the pressurewithin still 186 and initiate the flow of contaminated solvent from tank194 to the still. The distilled liquid solvent is pumped into vessel 142by pump 134 and transferred to tank through conduits 166, 164, tank 174and conduit 178 as described above. The distilled solvent in tank 180 isperiodically transferred to tank 12 by any conventional fluidcommunication means.

As will be apparent from the foregoing description, machine 10 includesmeans for removing impurities from the solvent filter quickly andeasily. Also, the machine includes an efficient closed fluid handlingsystem which minimizes the operating and maintenance expenses requiredfor removing solvent vapor from the cleaning chamber and condensing suchvapor.

Preferably, all of the valves employed in machine 10 except check valve168 and pressure relief valve 172 are electromechanical valves, such assolenoid operated valves, and the wash, extract and drying cycles arecontrolled by a programmable electronic or electromechanical controlmeans.

While the foregoing constitutes a detailed description of a preferredembodiment of the dry cleaning machine of the invention, it isrecognized that various modifications thereof will occur to thoseskilled in the art. Therefore the scope of the invention is to belimited solely by the scope of the appended claims.

I claim:

l. A dry cleaning machine comprising:

a storage means for storing a supply of liquid cleaning solvent;

a chamber for receiving articles to be cleaned;

a first fluid communication means connected be-' tween said storagemeans and said chamber for transferring liquid solvent from the storagemeans to the chamber and including a filter for removing impurities fromthe solvent;

a second fluid communication means connected between said chamber andsaid storage means for returning liquid solvent from the chamber to thestorage means;

means for removing solvent vapor from said chamber and condensing saidvopor; and

means for periodically removing impurities from said filter, saidremoval means comprising a trap in fluid communication with said storagemeans and including a removable cover, a foraminous bucket for retainingimpurities therein insertable into and removable from said trap whensaid cover is removed therefrom, a normally closed first valve meansconnected between said filter and said trap for selectively placing saidfilter in fluid communication with said trap, a normally closed secondvalve means connected to said trap and connectable to a source ofcompressed gas for selectively admitting compressed gas into said trap,and means connected between said first fluid communication means andsaid filter for backwashing the filter with liquid solvent from I saidstorage means, whereby said first valve means periodically is opened andsaid filter backwashed so that impurities in the filter are flushed intosaid trap and retained in said bucket, whereafter said first valve meansis closed and said second valve means is opened so that compressed gasis admitted into said trap to squeeze solvent from said retainedimpurities, whereafter said second valve means is closed, whereupon saidcover may be removed from said trap so that said bucket may be removedfrom the trap and the impurities retained in the bucket discarded.

2. A machine as recited in claim ll, wherein said vapor removal andcondensing means includes a vacuum pump connected to said chamber forremoving solvent vapor therefrom, a vapor condensation means connectedto said vacuum pump for condensing solvent vapor removed from thechamber, and a second storage means connected to said condensation meansfor storing liquid solvent condensed by said condensation means.

3. A machine as recited in claim 2, wherein said condensation meansincludes a pressure vessel interposed between. said vacuum pump and saidsecond storage means and within which solvent vapors are pressurized andcondensed.

' 4. A machine as recited in claim 3, wherein said condensation meansfurther includes a condenser interposed between said vacuum pump andsaid pressure vessel for cooling solvent vapor prior to the vaporentering the pressure vessel.

5. A machine as recited in claim 3, wherein said condensation meansfurther includes a condensation vessel and a transfer pump interposedbetween said vacuum pump and said pressure vessel with the condensationvessel being connected between the vacuum and transfer pumps and thetransfer pump being connected between the condensation and pressurevessels, whereby said transfer pump transfers solvent vapors from thecondensation vessel to the pressure vessel to thereby reduce thepressure in the condensation vessel and thus reduce the pressure headagainst which the vacuum pump operates.

6. A machine as recited in claim 5, wherein said condensation meansfurther includes a pair of condensers respectively interposed betweensaid vacuum pump and said condensation vessel and between said transferpump and said pressure vessel for cooling solvent vapor prior to thevapor entering the condensation and pressure vessels.

7. A machine as recited in claim 2, further comprising means forseparating water from liquid solvent interposed between saidcondensation means and said second storage means.

8. A dry cleaning machine as recited in claim 2, wherein said vacuumpump is of the liquid seal type and said condensation means is incommunication with said pump for providing liquid solvent to seal thepump.

9. A dry cleaning machine as recited in claim 2, further comprising aheat exchanger mounted in said chamber for heating and vaporizingsolvent therein.

10. A dry cleaning machine as recited in claim 9, fur ther comprising atemperature-sensitive control element mounted in said chamber andoperatively connected to said heat exchanger for regulating thetemperature of the gases within the chamber.

11. A dry cleaning machine as recited in claim 9, further comprising asolvent-sensing control element mounted in said chamber and operativelyconnected to said heat exchanger for controlling the operation of theheat exchanger so that when substantially all of the solvent in thechamber has been vaporized and removed therefrom, the heat exchangercools the gases within the chamber.

12. A dry cleaning machine as recited in claim 1, wherein said vaporremoval and condensing means includes a second storage means for storingliquid solvent condensed thereby; and further comprising a distillationmeans connected between said first-mentioned storage means and saidvapor removal and condensing means for distilling contaminated solventin said first storage means and transferring distilled solvent to saidsecond storage means.

13. A dry cleaning machine as recited in claim 1, wherein said firstfluid communication means further includes a pump for transferringliquid solvent from said storage means to said chamber.

14. A dry cleaning machine as recited in claim 1, further comprising abasket rotatably mounted in said chamber for holding articles to becleaned, said basket having perforations therein to facilitate thecirculation of gases therethrough and through the articles therein.

15. A dry cleaning machine as recited in claim 14, further comprising afan rotatably mounted in said chamber and disposed concentrically withrespect to said baskefto promote the circulation of gases through thebasket and the articles therein. t

1. A dry cleaning machine comprising: a storage means for storing asupply of liquid cleaning solvent; a chamber for receiving articles tobe cleaned; a first fluid communication means connected between saidstorage means and said chamber for transferring liquid solvent from thestorage means to the chamber and including a filter for removingimpurities from the solvent; a second fluid communication meansconnected between said chamber and said storage means for returningliquid solvent from the chamber to the storage means; means for removingsolvent vapor from said chamber and condensing said vopor; and means forperiodically removing impurities from said filter, said removal meanscomprising a trap in fluid communication with said storage means andincluding a removable cover, a foraminous bucket for retainingimpurities therein insertable into and removable from said trap whensaid cover is removed therefrom, a normally closed first valve meansconnected between said filter and said trap for selectively placing saidfilter in fluid communication with said trap, a normally closed secondvalve means connected to said trap and connectable to a source ofcompressed gas for selectively admitting compressed gas into said trap,and means connected between said first fluid communication means andsaid filter for backwashing the filter with liquid solvent from saidstorage means, whereby said first valve means periodically is opened andsaid filter backwashed so that impurities in the filter are flushed intosaid trap and retained in said bucket, whereafter said first valve meansis closed and said second valve means is opened so that compressed gasis admitted into said trap to squeeze solvent from said retainedimpurities, whereafter said second valve means is closed, whereupon saidcover may be removed from said trap so that said bucket may be removedfrom the trap and the impurities retained in the bucket discarded.
 2. Amachine as recited in claim 1, wherein said vapor removal and condensingmeans includes a vacuum pump connected to said chamber for removingsolvent vapor therefrom, a vapor condensation means connected to saidvacuum pump for condensing solvent vapor removed from the chamber, and asecond storage means connected to said condensation means for storingliquid solvent condensed by said condensation means.
 3. A machine asrecited in claim 2, wherein said condensation means includes a pressurevessel interposed between said vacuum pump and said second storage meansand within which solvent vapors are pressurized and condensed.
 4. Amachine as recited in claim 3, wherein said condensation means furtherincludes a condenser interposed between said vacuum pump and saidpressure vessel for cooling solvent vapor prior to the vapor enterinGthe pressure vessel.
 5. A machine as recited in claim 3, wherein saidcondensation means further includes a condensation vessel and a transferpump interposed between said vacuum pump and said pressure vessel withthe condensation vessel being connected between the vacuum and transferpumps and the transfer pump being connected between the condensation andpressure vessels, whereby said transfer pump transfers solvent vaporsfrom the condensation vessel to the pressure vessel to thereby reducethe pressure in the condensation vessel and thus reduce the pressurehead against which the vacuum pump operates.
 6. A machine as recited inclaim 5, wherein said condensation means further includes a pair ofcondensers respectively interposed between said vacuum pump and saidcondensation vessel and between said transfer pump and said pressurevessel for cooling solvent vapor prior to the vapor entering thecondensation and pressure vessels.
 7. A machine as recited in claim 2,further comprising means for separating water from liquid solventinterposed between said condensation means and said second storagemeans.
 8. A dry cleaning machine as recited in claim 2, wherein saidvacuum pump is of the liquid seal type and said condensation means is incommunication with said pump for providing liquid solvent to seal thepump.
 9. A dry cleaning machine as recited in claim 2, furthercomprising a heat exchanger mounted in said chamber for heating andvaporizing solvent therein.
 10. A dry cleaning machine as recited inclaim 9, further comprising a temperature-sensitive control elementmounted in said chamber and operatively connected to said heat exchangerfor regulating the temperature of the gases within the chamber.
 11. Adry cleaning machine as recited in claim 9, further comprising asolvent-sensing control element mounted in said chamber and operativelyconnected to said heat exchanger for controlling the operation of theheat exchanger so that when substantially all of the solvent in thechamber has been vaporized and removed therefrom, the heat exchangercools the gases within the chamber.
 12. A dry cleaning machine asrecited in claim 1, wherein said vapor removal and condensing meansincludes a second storage means for storing liquid solvent condensedthereby; and further comprising a distillation means connected betweensaid first-mentioned storage means and said vapor removal and condensingmeans for distilling contaminated solvent in said first storage meansand transferring distilled solvent to said second storage means.
 13. Adry cleaning machine as recited in claim 1, wherein said first fluidcommunication means further includes a pump for transferring liquidsolvent from said storage means to said chamber.
 14. A dry cleaningmachine as recited in claim 1, further comprising a basket rotatablymounted in said chamber for holding articles to be cleaned, said baskethaving perforations therein to facilitate the circulation of gasestherethrough and through the articles therein.
 15. A dry cleaningmachine as recited in claim 14, further comprising a fan rotatablymounted in said chamber and disposed concentrically with respect to saidbasket to promote the circulation of gases through the basket and thearticles therein.